Helium solubility in oxide nuclear fuel: Derivation of new correlations for Henry’s constant

Helium plays an important role in determining nuclear fuel performance both in-pile (especially for MOX fuels and at high burnup) and in storage conditions. Predictive models of helium behaviour are therefore a fundamental element in fuel performance codes. These models are based on the accurate knowledge of helium diffusivity (addressed in a previous paper, Luzzi et al., Nucl. Eng. Des., 330 (2018) 265-271 ) and of helium solubility in oxide nuclear fuel. Based on all the experimental data available in the literature and after verification of the validity of Henry's law, we propose two correlations for Henry's constant, kH (1/atm^3 / MPa) kH = 1.8 10^25 exp(-0.41/kT) for powders and kH = 4.1 10^24 exp(-0.65/kT) for single crystals; with the Boltzmann factor 1/kT in (1/eV). The correlation for Henry's constant in single-crystals is of interest for meso-scale models describing helium behaviour at the level of fuel grains. The current lack of data for this fundamental property, especially for poly-crystalline samples, cries for new experiments.

COGNINI Luana;  PIZZOCRI Davide;  BARANI Tommaso;  VAN UFFELEN Paul;  SCHUBERT Arndt;  WISS Thierry;  LUZZI Lelio; 

2018-12-06

ELSEVIER SCIENCE SA

JRC111578

0029-5493 (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC111578,   

10.1016/j.nucengdes.2018.09.024 (online),